Some pyrrolobenzodiazepines (PBDS) have the ability to recognise and bond to specific sequences of DNA; the preferred sequence is PuGPu. The first PBD antitumour antibiotic, anthramycin, was discovered in 1965 (Leimgruber, et al., J. Am. Chem. Soc., 87, 5793-5795 (1965); Leimgruber, et al., J. Am. Chem. Soc., 87, 5791-5793 (1965)). Since then, a number of naturally occurring PBDs have been reported, and over 10 synthetic routes have been developed to a variety of analogues (Thurston, et al., Chem. Rev. 1994, 433-465 (1994)). Family members include abbeymycin (Hochlowski, et al., J. Antibiotics, 40, 145-148 (1987)), chicamycin (Konishi, et al., J. Antibiotics, 37, 200-206 (1984)), DC-81 (Japanese Patent 58-180 487; Thurston, et al., Chem. Brit., 26, 767-772 (1990); Bose, et al., Tetrahedron, 48, 751-758 (1992)), mazethramycin (Kuminoto, et al., J. Antibiotics, 33, 665-667 (1980)), neothramycins A and B (Takeuchi, et al., J. Antibiotics, 29, 93-96 (1976)), porothramycin (Tsunakawa, et al., J. Antibiotics, 41, 1366-1373 (1988)), prothracarcin (Shimizu, et al, J. Antibiotics, 35, 972-978 (1982); Langley and Thurston, J. Org. Chem., 52, 91-97 (1987)), sibanomicin (DC-102) (Hara, et al., J. Antibiotics, 41, 702-704 (1988); Itoh, et al., J. Antibiotics, 41, 1281-1284 (1988)), sibiromycin (Leber, et al., J. Am. Chem. Soc., 110, 2992-2993 (1988)) and tomamycin (Arima, et al., J. Antibiotics, 25, 437-444 (1972)). PBDs are of the general structure:

They differ in the number, type and position of substituents, in both their aromatic A rings and pyrrolo C rings, and in the degree of saturation of the C ring. In the B-ring there is either an imine (N═C), a carbinolamine(NH—CH(OH)), or a carbinolamine methyl ether (NH—CH(OMe)) at the N10-C11 position which is the electrophilic centre responsible for alkylating DNA. All of the known natural products have an (S)-configuration at the chiral C11a position which provides them with a right-handed twist when viewed from the C ring towards the A ring. This gives them the appropriate three-dimensional shape for isohelicity with the minor groove of B-form DNA, leading to a snug fit at the binding site (Kohn, In Antibiotics III. Springer-Verlag, New York, pp. 3-11 (1975); Hurley and Needham-VanDevanter, Acc. Chem. Res., 19, 230-237 (1986)). Their ability to form an adduct in the minor groove, enables them to interfere with DNA processing, hence their use as antitumour agents.
A number of conjugates of PBD with pyrroles and imidazoles have been reported.
Lown has reported (Damayanthi, Y., et al., Journal of Organic Chemistry, 64(1), 290-292 (1999)) the synthesis of PBD conjugates (named PBD-lexitropsin conjugates):
wherein n=1-3 with a propyl linker and an N-dimethylaminopropyl terminus. Although these are stated to be lexitropsin derivatives with the n=2 and 3 analogues mimicking the 2 and 3 N-methylpyrrole rings of netropsin and distamycin, respectively, the N-dimethylaminopropyl tail differs significantly from the guanidine methyl or guanidine ethyl tails of netropsin or distamycin, respectively. The compounds, which were produced in an overall yield of 28-30% as a mixture of the N10-C11 imine and carbinolamine methyl ether forms. They were found to be highly polar as the imines and only soluble in a mixture of chloroform and methanol, and were insufficiently soluble in either solvent to allow production of pure imine or methyl ether forms. The compounds with n=2 and 3 were reported (Reddy, B. S. P., et al., Anti-Cancer Drug Design, 15(3), 225-238 (2000)) to have modest cytotoxicity with values ranging from 7.5-86.5 μM (for n=2) and 0.9-93 μM (for n=3).
Lown has also reported (Kumar, R. and Lown, J. W. Oncology Research, 13(4), 221-233 (2003)); Kumar, R., et al., Heterocyclic Communications, 8(1), 19-26 (2002)) the synthesis of three equivalent imidazole analogues:
wherein n=1-3 and two mixed pyrrole-imidazole analogues:
wherein n=1-2. These compounds, obtained in overall yields of 35-40% were also produced as mixtures of imines and carbinolamine methyl ethers in a 1:1 ratio, and had similar solubility characteristics. In the NCI 60 panel screen, the mixed compound (n=1) was not active in any cell lines, and the other compounds had mean GI50, TGI and LC50 values in the range 16.22-95.50 μM.
In an effort to enhance water solubility, Lown and co-workers more recently reported (Kumar, R., et al., Organic & Biomolecular Chemistry, 1(19), 3327-3342 (2003)) a set of sixteen PBD-heterocycle conjugates containing varying numbers of pyrrole and imidazole units but with heterocycles glycosylated on their ring nitrogens. In eight of these molecules the hydroxyl moieties of the glycosyl units were fully acetylated. The other eight were similar in structure except that all acetyl groups had been removed. Data from the NCl panel indicate that these compounds are significantly less cytotoxic than the corresponding compounds with glycosyl units. Also, although the group of compounds which are deacetylated are designed to be more water soluble than those which are acetylated, the average IC50 values show only a marginal improvement which in fact appears to be due to just one compound which shows a marked improvement (0.588 μM) over its non-deacetylated equivalent (93.3 μM). No DNA-binding data has been reported for any of these conjugates.
Baraldi and co-workers have reported (Baraldi, P. G., et al., Bioorganic & Medicinal Chemistry Letters, 8(21), 3019-3024 (1998)) the synthesis of a conjugate of a PBD and distamycin:
where n=3, which differs from the conjugates synthesized by Lown in having a two-methylene linker between the PBD and first heterocycle rather than three, and in possessing a guanidine terminus as found in the natural products distamycin and netropsin rather than the dimethylaminopropyl terminus of the Lown compounds. Interestingly, this compound appeared to be more cytotoxic than the Lown conjugates with an IC50 in K562 cells of 0.2 μM. The DNA binding of the conjugate was assessed in a PCR-based assay against DNA sequences that were GC-rich (Ha-ras oncogene) or AT-rich (oestrogen, ER) receptor. Unlike Distamycin A which inhibited PCR in only the AT-rich sequence, the compound was equipotent in inhibiting PCR in both the GC-rich and AT-rich DNAs at a level 6× more potent than Distamycin in the AT-rich sequence. Baraldi also reported (Baraldi, P. G., et al., Journal of Medicinal Chemistry, 42(25), 5131-5141 (1999)) an extended set of the compound above containing one to four pyrrole units (n=1-4). Cytotoxicity evaluations in K562 (>100 μM [n=1] to 0.04 μM [n=4]) and Jurkat (80 μM [for n=1] to 0.07 μM [for n=4]) cell lines showed that increase in the length of the polypyrrole backbone led to an increase of in vitro activity. Only the n=3 and 4 compounds were more potent than either the PBD fragment alone or the relevant tetrapyrrole devoid of PBD. To investigate sequence selectivity and stability of the drug/DNA complexes, DNase I footprinting and arrested polymerase chain reaction (PCR) were performed on fragments of the human c-myc oncogene and human immunodeficiency virus type 1 long terminal repeat (HIV-1 LTR) (both GC-rich), and the estrogen receptor gene (AT-rich). It was found that the ability of the compounds to arrest PCR of the c-myc gene (IC50=2-6 μM) and HIV gene (IC50=0.8-2.0 μM) was higher than distamycin A (25 μM for C-myc; 50 μM for HIV), suggesting that the presence of the PBD might be favouring a shift to GC-recognition. Interestingly, for the ER gene, compounds with n=1 or 2 were similar (IC50=3.0 μM, 2.0 μM, respectively) to distamycin (IC50=5 μM), whereas compounds with n=3 or 4 were marginally more active (0.8 μM, 0.2 μM, respectively) suggesting that there was a more profound effect on raising GC-selectivity. Analysis of arrest sites of ER PCR suggested that the compound where n=1 arrests at 5′-AGTTTAAA-3′, whereas the compounds where n=2-4 cause arrest at the same site and in addition at 5′-CATATATGTGTG-3′. Footprinting experiments suggested that comparing these compounds, similar footprints were obtained suggesting that changes in the number of pyrrole rings did not produce significant changes in sequence recognition. However, it was noted that the footprints generated by the compound where n=4 were larger than that generated by distamycin. Finally, using a PCR-based dialysis experiment, it was demonstrated that these hybrid compounds exhibit different DNA-binding activity with respect to both distamycin and the parent PBD. In addition, a direct relationship was found between number of pyrrole rings present in the hybrids and stability of drug/DNA complexes. Confirming the previous studies of Baraldi, Gambari and co-workers reported (Borgatti, M., et al., Drug Development Research, 60(3), 173-185 (2003)) the effects of these compounds on the interaction between purified NF-κB and [32P]-labelled oligomers mimicking the NF-κB HIV-1 LTR binding sites using both gel retardation (EMSA) and filter binding assays. The results showed that the conjugates were effective in inhibiting NF-κB p52/NF-κB DNA interactions according to the EMSA assay but only compounds where n=2-4 were active according to the filter assay. Similarly, conjugates where n=2-4 (but not n=1) were shown to efficiently inhibit HIV-1 LTR driven transcription in vitro whereas the PBD fragment alone was not. Baraldi and co-workers (Baraldi, P. G., et al., Nucleosides Nucleotides & Nucleic Acids, 19(8), 1219-1229 (2000)) also reported that the compound where n=3 inhibits binding of the transcription factor Sp1, a protein important for the control of transcription of cellular and viral genes, to its cognate DNA sequence. Nuclear proteins were isolated from K562 cells and immobilised on a filter after electrophoresis. The ability of the compound where n=3 to inhibit the binding of [32P]-labelled Sp1 oligomer to the filter was then studied. Although the PBD fragment or distamycin A failed to inhibit binding at concentrations of up to 50 μM, the compound where n=3 completely blocked the Sp1/DNA binding interaction at 10 μM, a result which was confirmed by gel shift experiments.
Finally, Gambari and co-workers have reported (Mischiati, C., et al., Biochemical Pharmacology, 67(3), 401-410 (2004)) that these compounds bind to TAR-RNA and inhibit TAR/protein(s) interaction, and also interact with structured TAR-RNA of HIV-1. The authors studied the effects of these compounds on protein/TAR-RNA interactions in vitro by both EMSA and filter binding experiments using nuclear extracts and Tat, and ex vivo using the HL3T1 cell line as a cellular system to study Tat-induced HIV-1 LTR driven transcription. The compounds bind TAR-RNA since they slow down migration of radiolabelled HIV-1 TAR-RNA, whereas distamycin A and the PBD fragment are inactive. In the EMSA experiments, binding of the compounds to either the structured AU-rich or GC-rich RNA was less efficient than to wild type TAR-RNA. Again the PBD fragment and distamycin A were inactive. Denaturing experiments suggested that the compounds where n=1 and 2 might be binding non-covalently to the DNA whereas the compounds where n=3 and 4 might be binding covalently. They also reported IC50 values in HL3T1 cells (72 hours) confirming earlier observed trends of cytotoxicity increasing with increasing numbers of pyrrole units attached.
Some of the present inventors have previously disclosed (Wells, G., et al., Proc. Am. Assoc. Canc. Res., 2003, 44, 452) the following compound:

The inventors have now discovered that the properties, particularly cytoxicity and DNA binding, of the prior art compounds can be improved.
A first aspect of the present invention provides a compound of formula I:
or a salt or solvate thereof, wherein:the dotted line indicates the optional presence of a double bond between C2 and C3;R2 is selected from —H, —OH, ═O, ═CH2, —CN, —R, OR, halo, ═CH—R, O—SO2—R, CO2R and COR;R7 is selected from H, R, OH, OR, SH, SR, NH2, NHR, NRR′, nitro, Me3Sn and halo;where R and R′ are independently selected from optionally substituted C1-7 alkyl, C3-20 heterocyclyl and C5-20 aryl groups;R10 and R11 either together form a double bond, or are selected from H and YRY, where Y is selected from O, S and NH and RY is H or C1-7 alkyl or H and SOxM, where x is 2 or 3, and M is a monovalent pharmaceutically acceptable cation;each X is independently a heteroarylene group;n is from 1 to 6;RE is C1-4 alkyl.
A second aspect of the present invention provides a compound of formula II:
wherein:the dotted line indicates the optional presence of a double bond between C2 and C3;R2 is selected from —H, —OH, ═O, ═CH2, —CN, —R, OR, halo, ═CH—R, O—SO2—R, CO2R and COR;R7 is selected from H, R, OH, OR, SH, SR, NH2, NHR, NRR′, nitro, Me3Sn and halo;where R and R′ are independently selected from optionally substituted C1-7 alkyl, C3-20 heterocyclyl and C5-20 aryl groups;R′10 is a nitrogen protecting group and R′11 is O—R12, wherein R12 is H or a hydroxyl protecting group;each X is independently a heteroarylene group;n is from 1 to 6;RE is C1-4 alkyl.
A third aspect of the present invention provides a method of synthesis of a compound of formula I comprising the deprotection of a compound of formula II.
A fourth aspect of the present invention provides a pharmaceutical composition comprising a compound of the first aspect of the invention and a pharmaceutically acceptable carrier or diluent.
A fifth aspect of the present invention provides a compound of the first aspect for use in a method of therapy.
A sixth aspect of the present invention provides the use of a compound of the first aspect of the invention in the manufacture of a medicament for the treatment of a proliferative disease.
A seventh aspect of the present invention provides a method of treatment of a patient suffering from a proliferative disease, comprising administering to said patient a therapeutically acceptable amount of a compound of the first aspect or a composition of the fourth aspect.
Definitions
Heteroarylene Group
X is an optionally substituted heteroarylene group, preferably a C5-16 heteroarylene group, more preferably a C5-10 heteroarylene group and even more preferably a C5-6 heteroarylene group. Furthermore in a preferred embodiment, the X group is a five membered heteroarylene group. The term “heteroarylene”, as used herein, pertains to a divalent moiety obtained by removing two hydrogen atoms from aromatic ring atoms of a heteroaromatic compound. Heteroarylene compounds as described herein correspond to heteroaryl groups as defined below with one fewer hydrogen atoms on the ring atoms.
The heteroarylene group (X) may contain one or more heteroatoms and preferably contains one heteroatom. The one or more heteroatoms in the heteroarylene group (X) are independently chosen from N, O and S and are preferably N.
The heteroarylene group (X) is optionally substituted with one or more R groups. In a preferred embodiment the X group is substituted at one or more of the heteroatom positions with at least one R group, most preferably the R group is a methyl or ethyl group.
The adjoining carbonyl and amino groups may be attached to the heteroarylene group (X) at any two of the heteroarylene atoms, and preferably at two separate carbon atoms in the heteroarylene ring.
Where the X group is a six membered heteroarylene group, the carbonyl and amino groups are preferably attached at the 2,6, 2,5, 3,6 or 3,5 positions.
Where the X group is a five membered heteroarylene group, the carbonyl and amino groups are preferably attached at the 2,5, 2,4 or 3,5 positions.
Where the X group comprises two fused rings, the carbonyl and amino groups are preferably attached to different rings.
Nitrogen Protecting Groups
Nitrogen protecting groups are well known in the art. Preferred nitrogen protecting groups are carbamate protecting groups that have the general formula:

A large number of possible carbamate nitrogen protecting groups are listed on pages 503 to 549 of Greene, T. W. and Wuts, G. M., Protective Groups in Organic Synthesis, 3rd Edition, John Wiley & Sons, Inc., 1999, which is incorporated herein by reference.
Particularly preferred protecting groups include Alloc, Troc, Teoc, BOC, Doc, Hoc, TcBOC, Fmoc, 1-Adoc and 2-Adoc.
Also suitable for use in the present invention are nitrogen protecting groups which can be removed in vivo (e.g. enzymatically, using light) as described in WO 00/12507, which is incorporated herein by reference. Examples of these protecting groups include:
which is nitroreductase labile (e.g. using ADEPT/GDEPT);
which are photolabile; and
which is glutathione labile (e.g. using NPEPT).Hydroxyl Protecting Groups
Hydroxyl protecting groups are well known in the art. A large number of suitable groups are described on pages 23 to 200 of Greene, T. W. and Wuts, G. M., Protective Groups in Organic Synthesis, 3rd Edition, John Wiley & Sons, Inc., 1999, which is incorporated herein by reference.
Classes of particular interest include silyl ethers, methyl ethers, alkyl ethers, benzyl ethers, esters, benzoates, carbonates, and sulfonates.
Substituents
The phrase “optionally substituted” as used herein, pertains to a parent group which may be unsubstituted or which may be substituted.
Unless otherwise specified, the term “substituted” as used herein, pertains to a parent group which bears one or more substitutents. The term “substituent” is used herein in the conventional sense and refers to a chemical moiety which is covalently attached to, or if appropriate, fused to, a parent group. A wide variety of substituents are well known, and methods for their formation and introduction into a variety of parent groups are also well known.
Examples of substituents are described in more detail below.
C1-7 alkyl: The term “C1-7 alkyl” as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from a carbon atom of a hydrocarbon compound having from 1 to 7 carbon atoms, which may be aliphatic or alicyclic, and which may be saturated or unsaturated (e.g. partially unsaturated, fully unsaturated). Thus, the term “alkyl” includes the sub-classes alkenyl, alkynyl, cycloalkyl, etc., discussed below.
Examples of saturated alkyl groups include, but are not limited to, methyl (C1), ethyl (C2), propyl (C3), butyl (C4), pentyl (C5), hexyl (C6) and heptyl (C7).
Examples of saturated linear alkyl groups include, but are not limited to, methyl (C1), ethyl (C2), n-propyl (C3), n-butyl (C4), n-pentyl (amyl) (C5), n-hexyl (C6) and n-heptyl (C7).
Examples of saturated branched alkyl groups include iso-propyl (C3), iso-butyl (C4), sec-butyl (C4), tert-butyl (C4), iso-pentyl (C5), and neo-pentyl (C5).
C2-7 Alkenyl: The term “C2-7 alkenyl” as used herein, pertains to an alkyl group having one or more carbon-carbon double bonds.
Examples of unsaturated alkenyl groups include, but are not limited to, ethenyl (vinyl, —CH═CH2), 1-propenyl (—CH═CH—CH3), 2-propenyl (allyl, —CH—CH═CH2), isopropenyl (1-methylvinyl, —C(CH3)═CH2), butenyl (C4), pentenyl (C5), and hexenyl (C6).
C2-7 alkynyl: The term “C2-7 alkynyl” as used herein, pertains to an alkyl group having one or more carbon-carbon triple bonds.
Examples of unsaturated alkynyl groups include, but are not limited to, ethynyl (ethinyl, —C≡CH) and 2-propynyl (propargyl, —CH2—C≡CH).
C3-7 cycloalkyl: The term “C3-7 cycloalkyl” as used herein, pertains to an alkyl group which is also a cyclyl group; that is, a monovalent moiety obtained by removing a hydrogen atom from an alicyclic ring atom of a cyclic hydrocarbon (carbocyclic) compound, which moiety has from 3 to 7 carbon atoms, including from 3 to 7 ring atoms.
Examples of cycloalkyl groups include, but are not limited to, those derived from                saturated monocyclic hydrocarbon compounds:            cyclopropane (C3), cyclobutane (C4), cyclopentane (C5), cyclohexane (C6), cycloheptane (C7), methylcyclopropane (C4), dimethylcyclopropane (C5), methylcyclobutane (C5), dimethylcyclobutane (C6), methylcyclopentane (C6), dimethylcyclopentane (C7) and methylcyclohexane (C7);            unsaturated monocyclic hydrocarbon compounds:            cyclopropene (C3), cyclobutene (C4), cyclopentene (C5), cyclohexene (C6), methylcyclopropene (C4), dimethylcyclopropene (C5), methylcyclobutene (C5), dimethylcyclobutene (C6), methylcyclopentene (C6), dimethylcyclopentene (C7) and methylcyclohexene (C7); and            saturated polycyclic hydrocarbon compounds:            norcarane (C7), norpinane (C7), norbornane (C7).
C3-20 heterocyclyl: The term “C3-20 heterocyclyl” as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from a ring atom of a heterocyclic compound, which moiety has from 3 to 20 ring atoms, of which from 1 to 10 are ring heteroatoms. Preferably, each ring has from 3 to 7 ring atoms, of which from 1 to 4 are ring heteroatoms.
In this context, the prefixes (e.g. C3-20, C3-7, C5-6, etc.) denote the number of ring atoms, or range of number of ring atoms, whether carbon atoms or heteroatoms. For example, the term “C5-6heterocyclyl”, as used herein, pertains to a heterocyclyl group having 5 or 6 ring atoms.
Examples of monocyclic heterocyclyl groups include, but are not limited to, those derived from:    N1: aziridine (C3), azetidine (C4), pyrrolidine (tetrahydropyrrole) (C5), pyrroline (e.g., 3-pyrroline, 2,5-dihydropyrrole) (C5), 2H-pyrrole or 3H-pyrrole (isopyrrole, isoazole) (C5), piperidine (C6), dihydropyridine (C6), tetrahydropyridine (C6), azepine (C7);    O1: oxirane (C3), oxetane (C4), oxolane (tetrahydrofuran) (C5), oxole (dihydrofuran) (C5), oxane (tetrahydropyran) (C6), dihydropyran (C6), pyran (C6), oxepin (C7);    S1: thiirane (C3), thietane (C4), thiolane (tetrahydrothiophene) (C5), thiane (tetrahydrothiopyran) (C6), thiepane (C7);    O2: dioxolane (C5), dioxane (C6), and dioxepane (C7);    O3: trioxane (C6);    N2: imidazolidine (C5), pyrazolidine (diazolidine) (C5), imidazoline (C5), pyrazoline (dihydropyrazole) (C5), piperazine (C6);    N1O1: tetrahydrooxazole (C5), dihydrooxazole (C5), tetrahydroisoxazole (C5), dihydroisoxazole (C5), morpholine (C6), tetrahydrooxazine (C6), dihydrooxazine (C6), oxazine (C6);    N1S1: thiazoline (C5), thiazolidine (C5), thiomorpholine (C6);    N2O1: oxadiazine (C6);    O1S1: oxathiole (C5) and oxathiane (thioxane) (C6); and,    N1O1S1: oxathiazine (C6).
Examples of substituted monocyclic heterocyclyl groups include those derived from saccharides, in cyclic form, for example, furanoses (C5), such as arabinofuranose, lyxofuranose, ribofuranose, and xylofuranse, and pyranoses (C6), such as allopyranose, altropyranose, glucopyranose, mannopyranose, gulopyranose, idopyranose, galactopyranose, and talopyranose.
C5-20 aryl: The term “C5-20 aryl”, as used herein, pertains to a monovalent moiety obtained by removing a hydrogen atom from an aromatic ring atom of an aromatic compound, which moiety has from 3 to 20 ring atoms. Preferably, each ring has from 5 to 7 ring atoms.
In this context, the prefixes (e.g. C3-20, C5-7, C5-6, etc.) denote the number of ring atoms, or range of number of ring atoms, whether carbon atoms or heteroatoms. For example, the term “C5-6 aryl” as used herein, pertains to an aryl group having 5 or 6 ring atoms.
The ring atoms may be all carbon atoms, as in “carboaryl groups”.
Examples of carboaryl groups include, but are not limited to, those derived from benzene (i.e. phenyl) (C6), naphthalene (C10), azulene (C10), anthracene (C14), phenanthrene (C14), naphthacene (C15), and pyrene (C16).
Examples of aryl groups which comprise fused rings, at least one of which is an aromatic ring, include, but are not limited to, groups derived from indane (e.g. 2,3-dihydro-1H-indene) (C9), indene (C9), isoindene (C9), tetraline (1,2,3,4-tetrahydronaphthalene (C10), acenaphthene (C12), fluorene (C13-), phenalene (C13), acephenanthrene (C15), and aceanthrene (C16).
Alternatively, the ring atoms may include one or more heteroatoms, as in “heteroaryl groups”. Examples of monocyclic heteroaryl groups include, but are not limited to, those derived from:    N1: pyrrole (azole) (C5), pyridine (azine) (C6);    O1: furan (oxole) (C5);    S1: thiophene (thiole) (C5);    N1O1: oxazole (C5), isoxazole (C5), isoxazine (C6);    N2O1: oxadiazole (furazan) (C5);    N3O1: oxatriazole (C5);    N1S1: thiazole (C5), isothiazole (C5);    N2: imidazole (1,3-diazole) (C6), pyrazole (1,2-diazole) (C5), pyridazine (1,2-diazine) (C6), pyrimidine (1,3-diazine) (C6) (e.g., cytosine, thymine, uracil), pyrazine (1,4-diazine) (C6);    N3: triazole (C5), triazine (C6); and,    N4: tetrazole (C5).
Examples of heteroaryl which comprise fused rings, include, but are not limited to C9 (with 2 fused rings) derived from benzofuran (O1), isobenzofuran (O1), indole (N1), isoindole (N1), indolizine (N1), indoline (N1), isoindoline (N1), purine (N4) (e.g., adenine, guanine), benzimidazole (N2), indazole (N2), benzoxazole (N1O1), benzisoxazole (N1O1), benzodioxole (O2), benzofurazan (N2O1), benzotriazole (N3), benzothiofuran (S1), benzothiazole (N1S1), benzothiadiazole (N2S);    C10 (with 2 fused rings) derived from chromene (O1), isochromene (O1), chroman (O1), isochroman (O1), benzodioxan (O2), quinoline (N1), isoquinoline (N1), quinolizine (N1), benzoxazine (N1O1), benzodiazine (N2), pyridopyridine (N2), quinoxaline (N2), quinazoline (N2), cinnoline (N2), phthalazine (N2), naphthyridine (N2), pteridine (N4);    C11 (with 2 fused rings) derived from benzodiazepine (N2);    C13 (with 3 fused rings) derived from carbazole (N1), dibenzofuran (O1), dibenzothiophene (S1), carboline (N2), perimidine (N2), pyridoindole (N2); and,    C14 (with 3 fused rings) derived from acridine (N1), xanthene (O1), thioxanthene (S1), oxanthrene (O2), phenoxathiin (O1S1), phenazine (N2), phenoxazine (N1O1), phenothiazine (N1S1), thianthrene (S2), phenanthridine (N1), phenanthroline (N2), phenazine (N2).
The above groups, whether alone or part of another substituent, may themselves optionally be substituted with one or more groups selected from themselves and the additional substituents listed below.
Halo: —F, —Cl, —Br, and —I.
Hydroxy: —OH.
Ether: —OR, wherein R is an ether substituent, for example, a C1-7 alkyl group (also referred to as a C1-7 alkoxy group, discussed below), a C3-20 heterocyclyl group (also referred to as a C3-20 heterocyclyloxy group), or a C5-20 aryl group (also referred to as a C5-20 aryloxy group), preferably a C1-7alkyl group.
Alkoxy: —OR, wherein R is an alkyl group, for example, a C1-7 alkyl group. Examples of C1-7 alkoxy groups include, but are not limited to, —OMe (methoxy), —OEt (ethoxy), —O(nPr) (n-propoxy), —O(iPr) (isopropoxy), —O(nBu) (n-butoxy), —O(sBu) (sec-butoxy), —O(iBu) (isobutoxy), and —O(tBu) (tert-butoxy).
Acetal: —CH(OR1)(OR2), wherein R1 and R2 are independently acetal substituents, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C6-20 aryl group, preferably a C1-7 alkyl group, or, in the case of a “cyclic” acetal group, R1 and R2, taken together with the two oxygen atoms to which they are attached, and the carbon atoms to which they are attached, form a heterocyclic ring having from 4 to 8 ring atoms. Examples of acetal groups include, but are not limited to, —CH(OMe)2, —CH(OEt)2, and —CH(OMe)(OEt).
Hemiacetal: —CH(OH)(OR1), wherein R1 is a hemiacetal substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of hemiacetal groups include, but are not limited to, —CH(OH)(OMe) and —CH(OH)(OEt).
Ketal: —CR(OR1)(OR2), where R1 and R2 are as defined for acetals, and R is a ketal substituent other than hydrogen, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples ketal groups include, but are not limited to, —C(Me)(OMe)2, —C(Me)(OEt)2, —C(Me)(OMe)(OEt), —C(Et)(OMe)2, —C(Et)(OEt)2, and —C(Et)(OMe)(OEt).
Hemiketal: —CR(OH)(OR1), where R1 is as defined for hemiacetals, and R is a hemiketal substituent other than hydrogen, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of hemiacetal groups include, but are not limited to, —C(Me)(OH)(OMe), —C(Et)(OH)(OMe), —C(Me)(OH)(OEt), and —C(Et)(OH)(OEt).
Oxo (keto, -one): ═O.
Thione (thioketone): ═S.
Imino (imine): ═NR, wherein R is an imino substituent, for example, hydrogen, C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably hydrogen or a C1-7 alkyl group. Examples of ester groups include, but are not limited to, ═NH, ═NMe, ═NEt, and ═NPh.
Formyl (carbaldehyde, carboxaldehyde): —C(═O)H.
Acyl (keto): —C(═O)R, wherein R is an acyl substituent, for example, a C1-7 alkyl group (also referred to as C1-7 alkylacyl or C1-7 alkanoyl), a C3-20 heterocyclyl group (also referred to as C3-20 heterocyclylacyl), or a C5-20 aryl group (also referred to as C5-20 arylacyl), preferably a C1-7 alkyl group. Examples of acyl groups include, but are not limited to, —C(═O)CH3 (acetyl), —C(═O)CH2CH3 (propionyl), —C(═O)C(CH3)3 (t-butyryl), and —C(═O)Ph (benzoyl, phenone).
Carboxy (carboxylic acid): —C(═O)OH.
Thiocarboxy (thiocarboxylic acid): —C(═S)SH.
Thiolocarboxy (thiolocarboxylic acid): —C(═O)SH.
Thionocarboxy (thionocarboxylic acid): —C(═S)OH.
Imidic acid: —C(═NH)OH.
Hydroxamic acid: —C(═NOH)OH.
Ester (carboxylate, carboxylic acid ester, oxycarbonyl): —C(═O)OR, wherein R is an ester substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of ester groups include, but are not limited to, —C(═O)OCH3, —C(═O)OCH2CH3, —C(═O)OC(CH3)3, and —C(═O)OPh.
Acyloxy (reverse ester): —OC(═O)R, wherein R is an acyloxy substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of acyloxy groups include, but are not limited to, —OC(═O)CH3 (acetoxy), —OC(═O)CH2CH3, —OC(═O)C(CH3)3, —OC(═O)Ph, and —OC(═O)CH2Ph.
Oxycarboyloxy: —OC(═O)OR, wherein R is an ester substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of ester groups include, but are not limited to, —OC(═O)OCH3, —OC(═O)OCH2CH3, —OC(═O)OC(CH3)3, and —OC(═O)OPh.
Amino: —NR1R2, wherein R1 and R2 are independently amino substituents, for example, hydrogen, a C1-7 alkyl group (also referred to as C1-7 alkylamino or di-C1-7 alkylamino), a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably H or a C1-7 alkyl group, or, in the case of a “cyclic” amino group, R1 and R2, taken together with the nitrogen atom to which they are attached, form a heterocyclic ring having from 4 to 8 ring atoms. Amino groups may be primary (—NH2), secondary (—NHR1), or tertiary (—NHR1R2), and in cationic form, may be quaternary (—+NR1R2R3). Examples of amino groups include, but are not limited to, —NH2, —NHCH3, —NHC(CH3)2, —N(CH3)2, —N(CH2CH3)2, and —NH Ph. Examples of cyclic amino groups include, but are not limited to, aziridino, azetidino, pyrrolidino, piperidino, piperazino, morpholino, and thiomorpholino.
Amido (carbamoyl, carbamyl, aminocarbonyl, carboxamide): —C(═O)NR1R2, wherein R1 and R2 are independently amino substituents, as defined for amino groups. Examples of amido groups include, but are not limited to, —C(═O)NH2, —C(═O)NHCH3, —C(═O)N(CH3)2, —C(═O)NHCH2CH3, and —C(═O)N(CH2CH3)2, as well as amido groups in which R1 and R2, together with the nitrogen atom to which they are attached, form a heterocyclic structure as in, for example, piperidinocarbonyl, morpholinocarbonyl, thiomorpholinocarbonyl, and piperazinocarbonyl.
Thioamido (thiocarbamyl): —C(═S)NR1R2, wherein R1 and R2 are independently amino substituents, as defined for amino groups. Examples of amido groups include, but are not limited to, —C(═S)NH2, —C(═S)NHCH3, —C(═S)N(CH3)2, and —C(═S)NHCH2CH3.
Acylamido (acylamino): —NR1C(═O)R2, wherein R1 is an amide substituent, for example, hydrogen, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably hydrogen or a C1-7 alkyl group, and R2 is an acyl substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20aryl group, preferably hydrogen or a C1-7 alkyl group. Examples of acylamide groups include, but are not limited to, —NHC(═O)CH3, —NHC(═O)CH2CH3, and —NHC(═O)Ph. R1 and R2 may together form a cyclic structure, as in, for example, succinimidyl, maleimidyl, and phthalimidyl:

Aminocarbonyloxy: —OC(═O)NR1R2, wherein R1 and R2 are independently amino substituents, as defined for amino groups. Examples of aminocarbonyloxy groups include, but are not limited to, —OC(═O)NH2, —OC(═O)NHMe, —OC(═O)NMe2, and —OC(═O)NEt2.
Ureido: —N(R1)CONR2R3 wherein R2 and R3 are independently amino substituents, as defined for amino groups, and R1 is a ureido substituent, for example, hydrogen, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably hydrogen or a C1-7 alkyl group. Examples of ureido groups include, but are not limited to, —NHCONH2, —NHCONHMe, —NHCONHEt, —NHCONMe2, —NHCONEt2, —NMeCONH2, —NMeCONHMe, —NMeCONHEt, —NMeCONMe2, and —NMeCONEt2.
Guanidino: —NH—C(═NH)NH2.
Tetrazolyl: a five membered aromatic ring having four nitrogen atoms and one carbon atom,

Imino: ═NR, wherein R is an imino substituent, for example, for example, hydrogen, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably H or a C1-7alkyl group. Examples of imino groups include, but are not limited to, ═NH, ═NMe, and ═NEt.
Amidine (amidino): —C(═NR)NR2, wherein each R is an amidine substituent, for example, hydrogen, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably H or a C1-7 alkyl group. Examples of amidine groups include, but are not limited to, —C(═NH)NH2, —C(═NH)NMe2, and —C(═NMe)NMe2.
Nitro: —NO2.
Nitroso: —NO.
Azido: —N3.
Cyano (nitrile, carbonitrile): —CN.
Isocyano: —NC.
Cyanato: —OCN.
Isocyanato: —NCO.
Thiocyano (thiocyanato): —SCN.
Isothiocyano (isothiocyanato): —NCS.
Sulfhydryl (thiol, mercapto): —SH.
Thioether (sulfide): —SR, wherein R is a thioether substituent, for example, a C1-7 alkyl group (also referred to as a C1-7alkylthio group), a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of C1-7 alkylthio groups include, but are not limited to, —SCH3 and —SCH2CH3.
Disulfide: —SS—R, wherein R is a disulfide substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group (also referred to herein as C1-7 alkyl disulfide). Examples of C1-7 alkyl disulfide groups include, but are not limited to, —SSCH3 and —SSCH2CH3.
Sulfine (sulfinyl, sulfoxide): —S(═O)R, wherein R is a sulfine substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of sulfine groups include, but are not limited to, —S(═O)CH3 and —S(═O)CH2CH3.
Sulfone (sulfonyl): —S(═O)2R, wherein R is a sulfone substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group, including, for example, a fluorinated or perfluorinated C1-7 alkyl group. Examples of sulfone groups include, but are not limited to, —S(═O)2CH3 (methanesulfonyl, mesyl), —S(═O)2CF3 (triflyl), —S(═O)2CH2CH3 (esyl), —S(═O)2C4F9 (nonaflyl), —S(═O)2CH2CF3 (tresyl), —S(═O)2CH2CH2NH2 (tauryl), —S(═O)2Ph (phenylsulfonyl, besyl), 4-methylphenylsulfonyl (tosyl), 4-chlorophenylsulfonyl (closyl), 4-bromophenylsulfonyl (brosyl), 4-nitrophenyl (nosyl), 2-naphthalenesulfonate (napsyl), and 5-dimethylaminonaphthalen-1-ylsulfonate (dansyl).
Sulfinic acid (sulfino): —S(═O)OH, —SO2H.
Sulfonic acid (sulfo): —S(═O)2OH, —SO3H.
Sulfinate (sulfinic acid ester): —S(═O)OR; wherein R is a sulfinate substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of sulfinate groups include, but are not limited to, —S(═O)OCH3 (methoxysulfinyl; methyl sulfinate) and —S(═O)OCH2CH3 (ethoxysulfinyl; ethyl sulfinate).
Sulfonate (sulfonic acid ester): —S(═O)2OR, wherein R is a sulfonate substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of sulfonate groups include, but are not limited to, —S(═O)2OCH3 (methoxysulfonyl; methyl sulfonate) and —S(═O)2OCH2CH3 (ethoxysulfonyl; ethyl sulfonate).
Sulfinyloxy: —OS(═O)R, wherein R is a sulfinyloxy substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of sulfinyloxy groups include, but are not limited to, —OS(═O)CH3 and —OS(═O)CH2CH3.
Sulfonyloxy: —OS(═O)2R, wherein R is a sulfonyloxy substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of sulfonyloxy groups include, but are not limited to, —OS(═O)2CH3 (mesylate) and —OS(═O)2CH2CH3 (esylate).
Sulfate: —OS(═O)2OR; wherein R is a sulfate substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of sulfate groups include, but are not limited to, —OS(═O)2OCH3 and —SO(═O)2OCH2CH3.
Sulfamyl (sulfamoyl; sulfinic acid amide; sulfinamide): —S(—O)NR1R2, wherein R1 and R2 are independently amino substituents, as defined for amino groups. Examples of sulfamyl groups include, but are not limited to, —S(═O)NH2, —S(═O)NH(CH3), —S(═O)N(CH3)2, —S(═O)NH(CH2CH3), —S(═O)N(CH2CH3)2, and —S(═O)NHPh.
Sulfonamido (sulfinamoyl; sulfonic acid amide; sulfonamide): —S(═O)2NR1R2, wherein R1 and R2 are independently amino substituents, as defined for amino groups. Examples of sulfonamido groups include, but are not limited to, —S(═O)2NH2, —S(═O)2NH(CH3), —S(═O)2N(CH3)2, —S(═O)2NH(CH2CH3), —S(═O)2N(CH2CH3)2, and —S(═O)2NHPh.
Sulfamino: —NR1S(═O)2OH, wherein R1 is an amino substituent, as defined for amino groups. Examples of sulfamino groups include, but are not limited to, —NHS(═O)2OH and —N(CH3)S(═O)2OH.
Sulfonamino: —NR1S(═O)2R, wherein R1 is an amino substituent, as defined for amino groups, and R is a sulfonamino substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of sulfonamino groups include, but are not limited to, —NHS(═O)2CH3 and —N(CH3)S(═O)2C6H5.
Sulfinamino: —NR1S(═O)R, wherein R1 is an amino substituent, as defined for amino groups, and R is a sulfinamino substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group. Examples of sulfinamino groups include, but are not limited to, —NHS(═O)CH3 and —N(CH3)S(═O)C6H5.
Phosphino (phosphine): —PR2, wherein R is a phosphino substituent, for example, —H, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably —H, a C1-7 alkyl group, or a C5-20 aryl group. Examples of phosphino groups include, but are not limited to, —PH2, —P(CH3)2, —P(CH2CH3)2, —P(t-Bu)2, and —P(Ph)2.
Phospho: —P(═O)2.
Phosphinyl (phosphine oxide): —P(═O)R2, wherein R is a phosphinyl substituent, for example, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably a C1-7 alkyl group or a C5-20 aryl group. Examples of phosphinyl groups include, but are not limited to, —P(═O)(CH3)2, —P(═O)(CH2CH3)2, —P(═O)(t-Bu)2, and —P(═O)(Ph)2.
Phosphonic acid (phosphono): —P(═O)(OH)2.
Phosphonate (phosphono ester): —P(═O)(OR)2, where R is a phosphonate substituent, for example, —H, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably —H, a C1-7 alkyl group, or a C5-20 aryl group. Examples of phosphonate groups include, but are not limited to, —P(═O)(OCH3)2, —P(═O)(OCH2CH3)2, —P(═O)(O-t-Bu)2, and —P(═O)(OPh)2.
Phosphoric acid (phosphonooxy): —OP(═O)(OH)2.
Phosphate (phosphonooxy ester): —OP(═O)(OR)2, where R is a phosphate substituent, for example, —H, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably —H, a C1-7 alkyl group, or a C5-20 aryl group. Examples of phosphate groups include, but are not limited to, —OP(═O)(OCH3)2, —OP(═O)(OCH2CH3)2, —OP(═O)(O-t-Bu)2, and —OP(═O)(OPh)2.
Phosphorous acid: —OP(OH)2.
Phosphite: —OP(OR)2, where R is a phosphite substituent, for example, —H, a C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably —H, a C1-7 alkyl group, or a C5-20 aryl group. Examples of phosphite groups include, but are not limited to, —OP(OCH3)2, —OP(OCH2CH3)2, —OP(O-t-Bu)2, and —OP(OPh)2.
Phosphoramidite: —OP(OR1)—NR22, where R1 and R2 are phosphoramidite substituents, for example, —H, a (optionally substituted) C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably —H, a C1-7 alkyl group, or a C5-20 aryl group. Examples of phosphoramidite groups include, but are not limited to, —OP(OCH2CH3)—N(CH3)2, —OP(OCH2CH3)—N(i-Pr)2, and —OP(OCH2CH2CN)—N(i-Pr)2.
Phosphoramidate: —OP(═O)(OR1)—NR22, where R1 and R2 are phosphoramidate substituents, for example, —H, a (optionally substituted) C1-7 alkyl group, a C3-20 heterocyclyl group, or a C5-20 aryl group, preferably —H, a C1-7 alkyl group, or a C5-20 aryl group. Examples of phosphoramidate groups include, but are not limited to, —OP(═O)(OCH2CH3)—N(CH3)2, —OP(═O)(OCH2CH3)—N(i-Pr)2, and —OP(═O)(OCH2CH2CN)—N(i-Pr)2.
Proliferative Diseases
One of ordinary skill in the art is readily able to determine whether or not a candidate compound treats a proliferative condition for any particular cell type. For example, assays which may conveniently be used to assess the activity offered by a particular compound are described in the examples below.
The term “proliferative disease” pertains to an unwanted or uncontrolled cellular proliferation of excessive or abnormal cells which is undesired, such as, neoplastic or hyperplastic growth, whether in vitro or in vivo.
Examples of proliferative conditions include, but are not limited to, benign, pre-malignant, and malignant cellular proliferation, including but not limited to, neoplasms and tumours (e.g. histocytoma, glioma, astrocyoma, osteoma), cancers (e.g. lung cancer, small cell lung cancer, gastrointestinal cancer, bowel cancer, colon cancer, breast carinoma, ovarian carcinoma, prostate cancer, testicular cancer, liver cancer, kidney cancer, bladder cancer, pancreas cancer, brain cancer, sarcoma, osteosarcoma, Kaposi's sarcoma, melanoma), leukemias, psoriasis, bone diseases, fibroproliferative disorders (e.g. of connective tissues), and atherosclerosis.
Any type of cell may be treated, including but not limited to, lung, gastrointestinal (including, e.g. bowel, colon), breast (mammary), ovarian, prostate, liver (hepatic), kidney (renal), bladder, pancreas, brain, and skin.
Methods of Treatment
As described above, the present invention provide the use of a compound of the first aspect of the invention in a method of therapy.
The term “therapeutically effective amount” is an amount sufficient to show benefit to a patient. Such benefit may be at least amelioration of at least one symptom. The actual amount administered, and rate and time-course of administration, will depend on the nature and severity of what is being treated. Prescription of treatment, e.g. decisions on dosage, is within the responsibility of general practitioners and other medical doctors.
A compound may be administered alone or in combination with other treatments, either simultaneously or sequentially dependent upon the condition to be treated. Examples of treatments and therapies include, but are not limited to, chemotherapy (the administration of active agents, including, e.g. drugs; surgery; and radiation therapy. If the compound of formula I or II bears a carbamate-based nitrogen protecting group which may be removed in vivo, then the methods of treatment described in WO 00/12507 (ADEPT, GDEPT and PDT) may be used.
Pharmaceutical compositions according to the present invention, and for use in accordance with the present invention, may comprise, in addition to the active ingredient, i.e. a compound of formula I, a pharmaceutically acceptable excipient, carrier, buffer, stabiliser or other materials well known to those skilled in the art. Such materials should be non-toxic and should not interfere with the efficacy of the active ingredient. The precise nature of the carrier or other material will depend on the route of administration, which may be oral, or by injection, e.g. cutaneous, subcutaneous, or intravenous.
Pharmaceutical compositions for oral administration may be in tablet, capsule, powder or liquid form. A tablet may comprise a solid carrier or an adjuvant. Liquid pharmaceutical compositions generally comprise a liquid carrier such as water, petroleum, animal or vegetable oils, mineral oil or synthetic oil. Physiological saline solution, dextrose or other saccharide solution or glycols such as ethylene glycol, propylene glycol or polyethylene glycol may be included. A capsule may comprise a solid carrier such a gelatin.
For intravenous, cutaneous or subcutaneous injection, or injection at the site of affliction, the active ingredient will be in the form of a parenterally acceptable aqueous solution which is pyrogen-free and has suitable pH, isotonicity and stability. Those of relevant skill in the art are well able to prepare suitable solutions using, for example, isotonic vehicles such as Sodium Chloride Injection, Ringer's Injection, Lactated Ringer's Injection. Preservatives, stabilisers, buffers, antioxidants and/or other additives may be included, as required.
Includes Other Forms
Unless otherwise specified, included in the above are the well known ionic, salt, solvate, and protected forms of these substituents. For example, a reference to carboxylic acid (—COOH) also includes the anionic (carboxylate) form (—COO−), a salt or solvate thereof, as well as conventional protected forms. Similarly, a reference to an amino group includes the protonated form (—N+HR1R2), a salt or solvate of the amino group, for example, a hydrochloride salt, as well as conventional protected forms of an amino group. Similarly, a reference to a hydroxyl group also includes the anionic form (—O−), a salt or solvate thereof, as well as conventional protected forms.
Isomers, Salts and Solvates
Certain compounds may exist in one or more particular geometric, optical, enantiomeric, diasteriomeric, epimeric, atropic, stereoisomeric, tautomeric, conformational, or anomeric forms, including but not limited to, cis- and trans-forms; E- and Z-forms; c-, t-, and r-forms; endo- and exo-forms; R-, S-, and meso-forms; D- and L-forms; d- and l-forms; (+) and (−) forms; keto-, enol-, and enolate-forms; syn- and anti-forms; synclinal- and anticlinal-forms; α- and β-forms; axial and equatorial forms; boat-, chair-, twist-, envelope-, and halfchair-forms; and combinations thereof, hereinafter collectively referred to as “isomers” (or “isomeric forms”).
Preferably compounds of the present invention have the following stereochemistry at the C11 position:

Note that, except as discussed below for tautomeric forms, specifically excluded from the term “isomers”, as used herein, are structural (or constitutional) isomers (i.e. isomers which differ in the connections between atoms rather than merely by the position of atoms in space). For example, a reference to a methoxy group, —OCH3, is not to be construed as a reference to its structural isomer, a hydroxymethyl group, —CH2OH. Similarly, a reference to ortho-chlorophenyl is not to be construed as a reference to its structural isomer, meta-chlorophenyl. However, a reference to a class of structures may well include structurally isomeric forms falling within that class (e.g. C1-7 alkyl includes n-propyl and iso-propyl; butyl includes n-, iso-, sec-, and tert-butyl; methoxyphenyl includes ortho-, meta-, and para-methoxyphenyl).
The above exclusion does not pertain to tautomeric forms, for example, keto-, enol-, and enolate-forms, as in, for example, the following tautomeric pairs: keto/enol (illustrated below), imine/enamine, amide/imino alcohol, amidine/amidine, nitroso/oxime, thioketone/enethiol, N-nitroso/hyroxyazo, and nitro/aci-nitro.

Note that specifically included in the term “isomer” are compounds with one or more isotopic substitutions. For example, H may be in any isotopic form, including 1H, 2H (D), and 3H (T); C may be in any isotopic form, including 12C, 13C, and 14C; O may be in any isotopic form, including 16O and 18O; and the like.
Unless otherwise specified, a reference to a particular compound includes all such isomeric forms, including (wholly or partially) racemic and other mixtures thereof. Methods for the preparation (e.g. asymmetric synthesis) and separation (e.g. fractional crystallisation and chromatographic means) of such isomeric forms are either known in the art or are readily obtained by adapting the methods taught herein, or known methods, in a known manner.
Unless otherwise specified, a reference to a particular compound also includes ionic, salt, solvate, and protected forms of thereof, for example, as discussed below.
It may be convenient or desirable to prepare, purify, and/or handle a corresponding salt of the active compound, for example, a pharmaceutically-acceptable salt. Examples of pharmaceutically acceptable salts are discussed in Berge, et al., J. Pharm. Sci., 66, 1-19 (1977).
For example, if the compound is anionic, or has a functional group which may be anionic (e.g. —COOH may be —COO−), then a salt may be formed with a suitable cation. Examples of suitable inorganic cations include, but are not limited to, alkali metal ions such as Na+ and K+, alkaline earth cations such as Ca2+ and Mg2+, and other cations such as Al3+. Examples of suitable organic cations include, but are not limited to, ammonium ion (i.e. NH4+) and substituted ammonium ions (e.g. NH3R+, NH2R2+, NHR3+, NR4+). Examples of some suitable substituted ammonium ions are those derived from: ethylamine, diethylamine, dicyclohexylamine, triethylamine, butylamine, ethylenediamine, ethanolamine, diethanolamine, piperazine, benzylamine, phenylbenzylamine, choline, meglumine, and tromethamine, as well as amino acids, such as lysine and arginine. An example of a common quaternary ammonium ion is N(CH3)4+.
If the compound is cationic, or has a functional group which may be cationic (e.g. —NH2 may be —NH3+), then a salt may be formed with a suitable anion. Examples of suitable inorganic anions include, but are not limited to, those derived from the following inorganic acids: hydrochloric, hydrobromic, hydroiodic, sulfuric, sulfurous, nitric, nitrous, phosphoric, and phosphorous.
Examples of suitable organic anions include, but are not limited to, those derived from the following organic acids: 2-acetyoxybenzoic, acetic, ascorbic, aspartic, benzoic, camphorsulfonic, cinnamic, citric, edetic, ethanedisulfonic, ethanesulfonic, fumaric, glucheptonic, gluconic, glutamic, glycolic, hydroxymaleic, hydroxynaphthalene carboxylic, isethionic, lactic, lactobionic, lauric, maleic, malic, methanesulfonic, mucic, oleic, oxalic, palmitic, pamoic, pantothenic, phenylacetic, phenylsulfonic, propionic, pyruvic, salicylic, stearic, succinic, sulfanilic, tartaric, toluenesulfonic, and valeric. Examples of suitable polymeric organic anions include, but are not limited to, those derived from the following polymeric acids: tannic acid, carboxymethyl cellulose.
It may be convenient or desirable to prepare, purify, and/or handle a corresponding solvate of the active compound. The term “solvate” is used herein in the conventional sense to refer to a complex of solute (e.g. active compound, salt of active compound) and solvent. If the solvent is water, the solvate may be conveniently referred to as a hydrate, for example, a mono-hydrate, a di-hydrate, a tri-hydrate, etc.
Compounds of formula I include compounds where a nucleophilic solvent (H2O, RAOH, RANH2, RASH) adds across the imine bond of the PBD moiety, which is illustrated below where the solvent is water or an alcohol (RAOH, where RA is an ether substituent as described above):

These forms can be called the carbinolamine and carbinolamine ether forms of the PBD. The balance of these equilibria depend on the conditions in which the compounds are found, as well as the nature of the moiety itself.
These compounds may be isolated in solid form, for example, by lyophilisation.
General Synthetic Routes
Compounds of formula I where R10 and R11 together form a double bond may be synthesised from compounds of formula II by removing the nitrogen and hydroxyl, if present, protecting groups from the corresponding compound of formula II. Such techniques are well known in the art, and are described, for example, in Greene, T. W. and Wuts, G. M., Protective Groups in Organic Synthesis, 3rd Edition, John Wiley & Sons, Inc., 1999. If both nitrogen and hydroxyl protecting groups are present, these are preferably selected to be removable by the same conditions.
If this deprotection is carried out in a solvent of formula HYRY, then R10 and R11 will be H and YRY respectively. Alternatively, these groups may be introduced by adding the compound to a different solvent to that in which the deprotection is carried out.
The conversion of compounds of formula I as discussed above to those having R11 as SOxM may be achieved by the addition of the appropriate bisulphite salt or sulphinate slat, followed by a purification step. Further methods are described in GB 2 053 894, which is herein incorporated by reference.
Compounds of formula II can be made by the coupling of compounds of Formula 3 and Formula 4:
under standard amide bond formation conditions, e.g. in the presence of HOBt or DMAP and EDCI. In the compound of formula 3, R′12 is preferably a hydroxyl protecting group.
Compounds of formula 3 can be synthesised in general following the methods described in WO 00/12506, which is herein incorporated by reference. In particular, the butanoic acid side chain can be introduced at any stage in the synthesis, usually with appropriate protecting groups in place. For example, the side chain can be formed by coupling a protected or precursor form to a hydroxy group on the benzene ring using e.g. Mitsunobo coupling.
Compounds of formula 4 can be synthesised by coupling the desired number of units of formula 5:
to a compound of formula 6:

Compounds of formula 6 are commercially available or readily synthesisable.
In order to achieve the addition of units of formula 5 in a controlled manner, these units are usually in the form of a compound of formula 7:
where Prot is an appropriate nitrogen protecting group, such as Boc. A compound of formula 7 is coupled to the compound of formula 6 under standard amide coupling conditions, following which the protecting group is removed. This yields a compound of formula 4, to which further units may be coupled, as desired. The compounds of formula 4 may be built up adding single units of formula 5 at a time, or by the addition of multiple units.Further Preferences
R2 is preferably selected from ═CH2, ═CH—R, where R is more preferably an optionally substituted C1-4 alkyl group, and —R, where R is more preferably an optionally substituted C5-20 aryl group. Particularly preferred groups for R2 include ═CH2, ═CH-Me, and an optionally substituted phenyl group.
R7 is preferably independently selected from H, OR, SH, SR, NH2, NHR, NRR′, and halo, and more preferably independently selected from H and OR, where R is preferably selected from optionally substituted C1-7 alkyl, C3-10 heterocyclyl and C5-10 aryl groups. Preferably R7 is OMe or H and most preferably OMe.
In some embodiments, it is preferred that R10 and R11 either form a double bond together or R11 is are selected from H and ORY, where RY is H or Me. In other embodiments, it is preferred that R11 is SO3M.
R′10 is preferably selected from BOC, Troc or alloc. R′11 is preferably THP or a silyl oxygen protecting group (for example TBS) and is most preferably THP.
RE is preferably C1-2 alkyl, and more preferably methyl.
A preferred class of heteroarylene groups are those having 5 ring atoms, and more preferred are those having heteroatoms selected from N and S, of which N is preferred.
If a N ring atom is present having an N-substituent, the N-substitutent is preferably a C1-4 alkyl group, which is more preferably methyl.
A particularly preferred sub-class of heteroarylene groups comprises the following three units:
of which N-methyl-pyrrole, N-methyl-imidazole and thiazole are more preferred.
Other preferred heteroarylene groups include those based on 2-(pyrrol-2-yl)benzimidazoles, 2(pyrrol-2-yl)imiazopyridines and 5-hydroxy(pyrrol-2-yl)benzimadozles.
n is preferably from 2 to 6, more preferably 2 to 5, and most preferably 2 to 3.